Morten Thrane Brünnich (September 30, 1737 - September 19, 1827) was a Danish zoologist and mineralogist.

Brünnich was born in Copenhagen, the son of a portrait painter. He studied oriental languages and theology, but soon became interested in natural history. He contributed his observations of insects to Erik Pontopiddan's Danske Atlas (1763-81). After being put in charge of the natural history collection of Judge Christian Fleischer he became interested in ornithology, and in 1763 he published Ornithologia Borealis, which included the details of many Scandinavian birds, some described for the first time.

Brünnich corresponded with many foreign naturalists including Linnaeus, Peter Simon Pallas and Thomas Pennant. He published his Entomologia in 1764. He then embarked on a long tour of Europe, spending time studying the fish of the Mediterranean Sea and publishing his Icthyologia Massiliensis on the subject in 1768.

On his return Brünnich took up the post of Lecturer in Natural History and Economy at Copenhagen University. Here he established a natural history museum and wrote a textbook for his students, the Zoologiae fundamenta.

Reference

• Biographies for Birdwatchers, by Barbara and Richard Mearns - ISBN 0124874223